1. Field of the Invention
The present invention relates to the forming of amorphous or near-amorphous, ternary films of W-Si-N on substrates at temperatures at or below about 450.degree. C., by chemical vapor deposition of WF.sub.6, SiH.sub.4 and NH.sub.3 and a carrier gas.
2. Description of Related Art
Experiments have established that films of amorphous or near-amorphous structure and metallic conductivity of a ternary composition W-Si-N can be synthesized by sputtering of a W.sub.5 Si.sub.3 target with argon that contains an admixture of nitrogen. As discussed by L. E. Halperin, et al., in "Silicon Schottky Barriers and p-n Junctions with Highly Stable Aluminum Contact Metallization", IEEE Electron Device Letters Vol. 12, No. 6, p. 309-311 (1991) and by E. Kolawa et al., in "Sputtered Ta-Si-N Diffusion Barriers in Cu Metallizations for Si", IEEE Electron Device Letters, Vol. 12, No. 6, p. 321-323 (1991), these films are excellent diffusion barriers for copper and other metals used as contact and interconnection materials in devices and integrated circuits of silicon and other semiconductors.
A drawback of the reactive sputter-deposition is the inadequate conformality of the film when it is deposited on a finely patterned non-planar substrate, as are typically encountered in advanced integrated circuits. Conformality is an essential requirement for diffusion barriers.